What is the greatest common factor of $9$ and $1$ ? Another way to say this is: $\operatorname{gcf}(9, 1) = {?}$
Answer: The greatest common factor is the largest number that is a factor of both $9$ and $1$ The factors of $9$ are $1$ $3$ , and $9$ The only factor of $1$ is $1$ Thus, the greatest common factor of $9$ and $1$ is $1$. $\operatorname{gcf}(9, 1) = 1$